class RelSMPlanOp : public RelSPJPlanOp

The Sort-merge Join plan operator

Inheritance:

Public Methods

virtual XxxErrCode	CloseHandle (XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray) Closes the scan this plan operator offers
virtual XxxErrCode	GetNextRecord (XxxSetCursor& SCsr, XxxRelation* *RelationArray, const XxxRecordSchema* Schema, XxxRecord*& ReturnRec) Gets the next record from this plan operator
virtual XxxErrCode	InitHandle (XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray) Initializes this plan operator
virtual const char*	PrintString () Returns a string representation of this plan operator
	RelSMPlanOp (int NumChildren, RelPlanOp* Children[], RelCatalogInfo* CatInfo, XxxValExprPlanList* ExprPlanList, XxxBooleanExpressionPlan** SelPredPlans, XxxBooleanExpressionPlan** JoinPredPlans, XxxBooleanExpressionPlan** ResidPredPlans, XxxBooleanExpressionPlan* InitPlan) Constructor
virtual	~RelSMPlanOp () Destructor

Protected Classes

class

Group Encapsulates the concept of a record group; maintains a linked- list of records and information on which attribute the join is based upon struct Member The linked-list node structure Member* members The head of the linked list Member* currentMember The cursor in scans int attrIndex The attribute of the records in the equality join condition XxxBool scanValid Whether or not the current scan is valid Group (int attrIndexNum) Constructor ~Group () Destructor int AttrIndex () Returns the index of the critical attribute of the contained records XxxBool IsEmpty () Returns XXX_TRUE if this group has no records in it void AddRecord (XxxRecord *Rec) Adds a record to this group void FlushAllRecords (XxxBool DestroyRecs) Removes all records from this group void InitScan () Initializes a scan over the group XxxBool ScanIsValid () Returns XXX_TRUE if the current scan is valid XxxRecord* GetNext () Gets the next record from the scan void CloseScan () Closes the current scan

class

SMJoinInfo Contains the relevant information to store in the operator handle between calls to GetNextRecord XxxBool Valid Is the scan valid? int LeftRelIndex The indices of the left and right relations in the RelationArray Group LeftGroup The left, right, and output group structures SMJoinInfo (int RightRelIndex, int LeftRelIndex, int RightAttrIndex, int LeftAttrIndex) Constructor

Protected Methods

virtual XxxErrCode	createJoinInfo (XxxDerivedRelation::CursorInfo* Handle, SMJoinInfo *&JoinInfo) Creates the join info object for the SM run
virtual XxxErrCode	getNextItem (XxxRelation* *RelationArray, XxxDerivedRelation::CursorInfo* Handle, int Index, XxxBool& Valid) Gets the next record from the relation in the RelationArray indexed by the parameter
virtual XxxBool	isEqual (XxxRecord *LeftRec, int LeftAttrIndex, XxxRecordSchema *LeftSchema, XxxRecord *RightRec, int RightAttrIndex, XxxRecordSchema *RightSchema) Compares a left and right record and returns XXX_TRUE if they are equal with respect to their critical attributes
virtual XxxBool	isLessThan (XxxRecord *LeftRec, int LeftAttrIndex, XxxRecordSchema *LeftSchema, XxxRecord *RightRec, int RightAttrIndex, XxxRecordSchema *RightSchema) Compares a left and right record and returns XXX_TRUE if the left is less than the right with respect to their critical attributes
virtual XxxErrCode	joinGroups (XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray, const XxxRecordSchema* Schema, SMJoinInfo *JoinInfo) Joins the left and right groups by a cross-product (assuming the groups ought to be joined) and populates the output group
virtual XxxErrCode	parseJoinPlan (XxxDerivedRelation::CursorInfo* Handle, int &LeftAttrIndex, int &LeftRelIndex, int &RightAttrIndex, int &RightRelIndex) Parses the join plan, finding the location of the left and right relations and finding the indices of the critical attributes in each's records

Inherited from RelSPJPlanOp:

Inherited from RelDerivedPlanOp:

Inherited from RelPlanOp:

class Group

Encapsulates the concept of a record group; maintains a linked- list of records and information on which attribute the join is based upon

struct Member

The linked-list node structure

Member* members

The head of the linked list

Member* currentMember

The cursor in scans

int attrIndex

The attribute of the records in the equality join condition

XxxBool scanValid

Whether or not the current scan is valid

Group(int attrIndexNum)

Constructor

~Group()

Destructor

int AttrIndex()

Returns the index of the critical attribute of the contained records

XxxBool IsEmpty()

Returns XXX_TRUE if this group has no records in it

void AddRecord(XxxRecord *Rec)

Adds a record to this group

void FlushAllRecords(XxxBool DestroyRecs)

Removes all records from this group

Parameters:

DestroyRecs - If XXX_TRUE, the records within will be explicitly destroyed; otherwise, only the linked-list structure will be destroyed.

void InitScan()

Initializes a scan over the group

XxxBool ScanIsValid()

Returns XXX_TRUE if the current scan is valid

XxxRecord* GetNext()

Gets the next record from the scan. Returns NULL if the scan is now invalid.

void CloseScan()

Closes the current scan

class SMJoinInfo

Contains the relevant information to store in the operator handle between calls to GetNextRecord

XxxBool Valid

Is the scan valid?

int LeftRelIndex

The indices of the left and right relations in the RelationArray

Group LeftGroup

The left, right, and output group structures

SMJoinInfo(int RightRelIndex, int LeftRelIndex, int RightAttrIndex, int LeftAttrIndex)

Constructor

virtual XxxErrCode createJoinInfo(XxxDerivedRelation::CursorInfo* Handle, SMJoinInfo *&JoinInfo)

Creates the join info object for the SM run

virtual XxxErrCode getNextItem(XxxRelation* *RelationArray, XxxDerivedRelation::CursorInfo* Handle, int Index, XxxBool& Valid)

Gets the next record from the relation in the RelationArray indexed by the parameter. Returns Valid == XXX_TRUE if the next record was returned.

virtual XxxErrCode joinGroups(XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray, const XxxRecordSchema* Schema, SMJoinInfo *JoinInfo)

Joins the left and right groups by a cross-product (assuming the groups ought to be joined) and populates the output group. In the process, it empties the input groups.

virtual XxxErrCode parseJoinPlan(XxxDerivedRelation::CursorInfo* Handle, int &LeftAttrIndex, int &LeftRelIndex, int &RightAttrIndex, int &RightRelIndex)

Parses the join plan, finding the location of the left and right relations and finding the indices of the critical attributes in each's records

virtual XxxBool isEqual(XxxRecord *LeftRec, int LeftAttrIndex, XxxRecordSchema *LeftSchema, XxxRecord *RightRec, int RightAttrIndex, XxxRecordSchema *RightSchema)

Compares a left and right record and returns XXX_TRUE if they are equal with respect to their critical attributes

virtual XxxBool isLessThan(XxxRecord *LeftRec, int LeftAttrIndex, XxxRecordSchema *LeftSchema, XxxRecord *RightRec, int RightAttrIndex, XxxRecordSchema *RightSchema)

Compares a left and right record and returns XXX_TRUE if the left is less than the right with respect to their critical attributes

virtual const char* PrintString()

Returns a string representation of this plan operator

virtual XxxErrCode GetNextRecord(XxxSetCursor& SCsr, XxxRelation* *RelationArray, const XxxRecordSchema* Schema, XxxRecord*& ReturnRec)

Gets the next record from this plan operator

virtual XxxErrCode InitHandle(XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray)

Initializes this plan operator

virtual XxxErrCode CloseHandle(XxxDerivedRelation::CursorInfo* Handle, XxxRelation* *RelationArray)

Closes the scan this plan operator offers

RelSMPlanOp(int NumChildren, RelPlanOp* Children[], RelCatalogInfo* CatInfo, XxxValExprPlanList* ExprPlanList, XxxBooleanExpressionPlan** SelPredPlans, XxxBooleanExpressionPlan** JoinPredPlans, XxxBooleanExpressionPlan** ResidPredPlans, XxxBooleanExpressionPlan* InitPlan)

Constructor

virtual ~RelSMPlanOp()

Destructor

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